Here's how a normal Datafeedr product update works:
- You click the [Update Products and Settings] button (or update runs automatically).
- Every search subscription in the Factory is run.
- All products that merchants have available are returned that match your subscriptions.
- On your site, all products are deleted.
- Then all of the new products which were just found in the searches are imported.
So, after an update, no products which are no longer available are removed from your store. And any new products that do match your searches are now in your store.
Updates are, by default, handled automatically every 3 days. You can change that interval here: The Factory > Your Store > Store menu > Basic Store Settings